Dementia exists in several forms including static dementia, Alzheimer's-type dementia, senile dementia, pre-senile dementia and progressive dementia. One of the common pathological features of several types of dementia is the lack of the neurotransmitter acetylcholine. This has led to the development of acetylcholine esterase inhibitors for use in the treatment of dementias such as the compound tacrine. A summary of the different approaches to and progress made in the treatment of Alzheimer's Disease may be found in Drugs of the Future (1995) 20(11): 1145-1162.
Recently, compounds that in addition to inhibiting acetylcholine esterase, possess inhibitory activity against monoamine oxidase type A (MAO-A) have been developed. The perceived benefit of having the anti-MAO-A activity is stated to be an anti-depressant effect (European Patent Publication Nos. 614,888 and 664,291).
U.S. Pat. Nos. 5,387,133, 5,453,446, 5,457,133 and 5,519,061 all disclose that the compound (R)-N-propargyl-1-aminoindan, a highly selective monoamine oxidase type B (MAO-B) inhibitor is effective in the treatment of dementias of the Alzheimer type and memory disorders. There is no indication given therein that the compound might have acetylcholine esterase inhibitory activity. Furthermore, the compound is only very weakly active as a MAO-A inhibitor.
PCT International Publication No. WO95/18617 discloses various aminoindan derivatives that are active in a variety of CNS disorders including dementias of the Alzheimer type. There is no indication given therein that any of the compounds disclosed might have acetylcholine esterase inhibitory activity.